Physics (Internal)

Exact critical exponents for the antiferromagnetic quantum critical point in and dimensions

This event is part of the Condensed Matter Theory Seminar Series.

The antiferromagnetic quantum critical point is believed to exist in many unconventional superconductors, such as high-Tc cuprates, heavy fermion compounds and iron-based superconductors. The strange metal state above this critical point is the most common kind of non-Fermi liquid found in nature, and, therefore, gaining a theoretical understanding of it is a key problem in condensed matter. We present a controlled approach to this problem using a dimensional regularization technique, extending the spatial dimension from to . We find an emergent control parameter, which allows us to find exact values for the critical exponents of the theory within a finite window of . We then use these exponents as an ansatz for the problem directly in . We again find the same emergent control parameter, and we confirm that our ansatz is exact in the IR. This gives us an exact description of the low-energy physics, in which both fermions and bosons do not have quasi-particle-like excitations, and the specific heat of the system violates hyperscaling.